Hitherto, air-conditioning apparatuses have been known that are provided with an outdoor unit including a compressor and an outdoor heat exchanger; a plurality of indoor units, each having an indoor heat exchanger; and a relay unit which connects the outdoor unit and the indoor unit to each other and is capable of performing a cooling operation (heating only operation mode) or a heating operation (heating only operation mode) with all the plurality of indoor units or a cooling operation with some indoor units and a heating operation with the other indoor units at the same time (cooling-main operation mode in which a cooling operation capacity is larger than a heating operation capacity or a heating-main operation mode in which the heating operation capacity is larger than the cooling operation capacity).
As such an apparatus, there has been proposed “an air-conditioning apparatus in which a first branching section which switchably connects one of a plurality of indoor units to a first connection pipeline or a second connection pipeline and a second branching section which connects the other of the plurality of the indoor units to the second connection pipeline through a first flow control device connected to the indoor units, the first branching section and the second branching section are connected through a second flow control device, and a relay unit incorporating the first branching section, the second flow control device, and the second branching section is interposed between a heat source unit and the plurality of indoor units, and the heat source unit and the relay unit are connected by the first and second connection pipelines extending therebetween” is proposed (See Patent Document 1, for example).
Also, there has been proposed “a refrigeration cycle device comprising a first refrigerant cycle having at least one compressor, at least one outdoor heat exchanger, a first expansion device capable of changing an opening degree, a high-pressure pipeline installed in a vertical direction of a building having a plurality of floors, and a low-pressure pipeline; and a second refrigerant cycle having a second expansion device capable of changing an opening degree, an indoor heat exchanger, a gas pipeline installed in a horizontal direction of each floor, and a liquid pipeline and being installed on a predetermined floor of the building; characterized by having a first intermediate heat exchanger provided on a pipeline annularly connected to the high-pressure pipeline and exchanging heat between the first refrigerant cycle and the second refrigerant cycle during a heating operation and a second intermediate heat exchanger provided on a pipeline annularly connected to the low-pressure pipeline and exchanging heat between the first refrigerant cycle and the second refrigerant cycle during a cooling operation” (See Patent Document 2, for example).
[Patent Document 1] Japanese Unexamined Patent Application Publication No. 2-118372 (Page 3, FIG. 1)
[Patent Document 2] Japanese Unexamined Patent Application Publication No. 2003-343936 (Page 5, FIG. 1)